static void tb_scan_port()

in tb.c [579:695]

• 69 lines of code
• 23 McCabe index (conditional complexity)

static void tb_scan_port(struct tb_port *port)
{
	struct tb_cm *tcm = tb_priv(port->sw->tb);
	struct tb_port *upstream_port;
	struct tb_switch *sw;

	if (tb_is_upstream_port(port))
		return;

	if (tb_port_is_dpout(port) && tb_dp_port_hpd_is_active(port) == 1 &&
	    !tb_dp_port_is_enabled(port)) {
		tb_port_dbg(port, "DP adapter HPD set, queuing hotplug\n");
		tb_queue_hotplug(port->sw->tb, tb_route(port->sw), port->port,
				 false);
		return;
	}

	if (port->config.type != TB_TYPE_PORT)
		return;
	if (port->dual_link_port && port->link_nr)
		return; /*
			 * Downstream switch is reachable through two ports.
			 * Only scan on the primary port (link_nr == 0).
			 */
	if (tb_wait_for_port(port, false) <= 0)
		return;
	if (port->remote) {
		tb_port_dbg(port, "port already has a remote\n");
		return;
	}

	tb_retimer_scan(port, true);

	sw = tb_switch_alloc(port->sw->tb, &port->sw->dev,
			     tb_downstream_route(port));
	if (IS_ERR(sw)) {
		/*
		 * If there is an error accessing the connected switch
		 * it may be connected to another domain. Also we allow
		 * the other domain to be connected to a max depth switch.
		 */
		if (PTR_ERR(sw) == -EIO || PTR_ERR(sw) == -EADDRNOTAVAIL)
			tb_scan_xdomain(port);
		return;
	}

	if (tb_switch_configure(sw)) {
		tb_switch_put(sw);
		return;
	}

	/*
	 * If there was previously another domain connected remove it
	 * first.
	 */
	if (port->xdomain) {
		tb_xdomain_remove(port->xdomain);
		tb_port_unconfigure_xdomain(port);
		port->xdomain = NULL;
	}

	/*
	 * Do not send uevents until we have discovered all existing
	 * tunnels and know which switches were authorized already by
	 * the boot firmware.
	 */
	if (!tcm->hotplug_active)
		dev_set_uevent_suppress(&sw->dev, true);

	/*
	 * At the moment Thunderbolt 2 and beyond (devices with LC) we
	 * can support runtime PM.
	 */
	sw->rpm = sw->generation > 1;

	if (tb_switch_add(sw)) {
		tb_switch_put(sw);
		return;
	}

	/* Link the switches using both links if available */
	upstream_port = tb_upstream_port(sw);
	port->remote = upstream_port;
	upstream_port->remote = port;
	if (port->dual_link_port && upstream_port->dual_link_port) {
		port->dual_link_port->remote = upstream_port->dual_link_port;
		upstream_port->dual_link_port->remote = port->dual_link_port;
	}

	/* Enable lane bonding if supported */
	tb_switch_lane_bonding_enable(sw);
	/* Set the link configured */
	tb_switch_configure_link(sw);
	if (tb_switch_enable_clx(sw, TB_CL0S))
		tb_sw_warn(sw, "failed to enable CLx on upstream port\n");

	tb_switch_tmu_configure(sw, TB_SWITCH_TMU_RATE_HIFI,
				tb_switch_is_clx_enabled(sw));

	if (tb_enable_tmu(sw))
		tb_sw_warn(sw, "failed to enable TMU\n");

	/* Scan upstream retimers */
	tb_retimer_scan(upstream_port, true);

	/*
	 * Create USB 3.x tunnels only when the switch is plugged to the
	 * domain. This is because we scan the domain also during discovery
	 * and want to discover existing USB 3.x tunnels before we create
	 * any new.
	 */
	if (tcm->hotplug_active && tb_tunnel_usb3(sw->tb, sw))
		tb_sw_warn(sw, "USB3 tunnel creation failed\n");

	tb_add_dp_resources(sw);
	tb_scan_switch(sw);
}